Induction-motor.



C. L. SPINNEY.

INDUCTION MOTOR.

APPLICATION FILED sEPT.3o,1912.

` Patented 111111311914.

-proje'cting ends ot' the conductor bars to' UNITED sTATEs PATENT oEEioE.

CHARLES L. SPINNEY, .OF LYNN, MASSACHUSETTS, ASSIGNOR TOi GENERAL E12|ECUBJC COMPANY, A CORPORATION 0F NEW YORK.

INDUCTION-Moron.

i Specification of Letters Patent.

Patented Mar. 31, 1914.

Application led September 30, 1912. Serial No. 723,047.

To all whom. it may concer/t.'

-Be it known that I, CHARLES L. SPINNEY, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Induction-Motors, ot' which the following is a speciication.

The present invention relates to the construction of induction motor armatures, and particularly to the casting of windings upon the iron core.

The well-known squirrel-cage induction motor armature` or rotor, consists of a cylindrical iron core in which are embedded conductor bars ordinarily consisting/of copper. These conductors are connected at each end b v Vwhat is known as short-circuiting rings, or simply end rings. The bars formel-ly have been mechanically inserted in the core and either soldered, or welded to the end ringsl or the end rings have been cast against the drawn conductors. .These operations are necessarily expensive.A Solj dering has an additional disadvantage, for when the motor is operated at an overload the resulting high temperature is apt to 'cause the soldering met-al to melt, and injure the motor. The invention of Dr. Ezechiel lVeintraub for a methodof 'casting copper as disclosed in Patent #1,023,604 of April 16, 101.2, has made'it possible to cast both the copper conductors and end rings in position 1n a single operation. Although small sizedrotors may be cast without special diiiiculty and without change of the design heretofore used, it has been found that diiiiculty experienced when casting the winding of large rotors. The end rings shrink in size, causing a radial stress upon the conductors toward the shaft, and 're' sulting in rupture either of the bars or end lungs. I have discovered that this diiliculty may be avoided by inclining or canting' the the ends of the core at an angle less than 90 degrees, preferably about 45 degrees. When bars of a rectangular `section are used it is advisable sometimes but not necessary to arrange the mold so as lo give a twist or turn to the projecting ends -oi the bars, rotating the major axis outside of the core. at an angle to the major axis within the core, in this manner bringing the strains caused by shrinkage of the end ring to bear upon the lesser diameter.

Uy invention will be pointed out with greater particularity in the appended claims. For a more complete understanding of my invention reference may be had to the accompanying drawings taken in connection with the following description.

Figure l is a front .elevation partly in section of a completed rotor; Fig. 2 is a fragmental sectional side` View showing how the ends of the bars are twisted; Fig. l3 is an enlarged fragmental perspective view 'of a single bar andV Fig. 4 is a somewhat diagrannnatic view showing the relations of ,the twisted ends of the bars.

Referring to Fig. 1 the core l, commonly consists of laminations of magnetic steel, or

iron clamped together by plates 2, 2. Through this core pass conductor bars, 3, shown particularly in the sectional. part ot' the core just below shaft 4. As here illustrated the bars extend longitudinally through the core at right angles to the core sides but 'this is not necessarily the case. The ends of the bars projectpsome distance beyond the core substantially within an eX- tension of a cylindrical'surface of the core and are integrally bound together by end rings .5, 5. lThe projecting ends of the bars, or pins, 6 between the core and the short-circuiting rings are inclined about 60 or less with respect to the core face, substantially in a plane parallel to the axis of the core, as clearly shown in Fig. 2. AIn

other words, instead of projecting vat right 'i angles to the core face, they are bent at an angle of at least 300 usually about 45 out of a vertical position, as best shown in Fig.

twisting or partial rotation ot' the pins 6,

as illustrated particularly in Fig. 4 and by sections 7 and 8 in Fig. 2, is used in some cases when the bars have a substantially rectangular cross-section. In this manner the radial inward stress caused by the shrinking of the ring is more easily taken up by the projecting pins. f

The above construction, or" course, Will appiy also to metals other than copper, such as brass which may be used in case higher resistance armatures are desired.

TWhat claim as new and desire, to secure by Letters Patent of the United States, is,

l. An induction motor rotor comprising a magnetic core, conductors passing there-l through and projecting outside said core at an angle of less than 90 degrees With respect to the face of said core, the projecting ends of said conductors being located substantially Within an extension of the cylindrical surface of the core and a short-cir cuiting ring connecting and forming an integral part of said conductors.

2. ln an induction motor, the combination of an iron core, cast metal bars passing therethrough and projecting beyond said core, said projecting ends extending at an angle of about 45 degrees to a line passing longitudinally through said core and located substantially Within an extension of the cylindrical surface of the core, and a cast conr ductor short-circuiting said bars.

3. An induction motor rotor,com]j rising,a

cylindrical core of magnetic material, cop- ,longitudinally per conductors passing through said core near its peripheral surface and extending beyond the ends ot' said core. said projections being canted at an angle of I i 1 l mamie less than 60 degrees, and copper rings binding the respective ends of said conductors together, said conductors and rings forming a single mass of-copper Without mechanical joints.

4. An induction motor rotor comprising a cylindrical iron core, substantially rectangular vbars passing through said core so that the major axes are radially disposed, the ends of said bars projecting beyond the sides of the core at an angle less than 90 degrees said projecting ends being rotated or twisted so as to incline the major axes and a metal ring. integrally connecting said bars,

5. An induction motor rotor, comprising a. y

cylindrical iron core, substantially rectangular cast copper bars passing through said core iear its peripheral surface `and having their major axes radiali disposed, the ends of said bars projecting eyond the faces of said core at an angle less ythan 90 degrees, said projectingends being located substanti'ally in a plane parallel to the axis of said core and a cast copper ring integrally connecting said bars. i

In Witness whereof, I have hereunto set my hand this QTthday of September, 1912.

CHARLES L. SPINNEY. Witnesses: Y

JOHN A. McMANUs, Jr., FRANK H. JoHNsoN. 

